Housings of high power semiconductor devices usually comprise a cathode and an anode. The respective electrodes are in contact with the semiconductor element which is placed between the electrodes and enable the current flow through the high power semiconductor device. The cathode and anode electrodes may be connected to a ceramic ring that enables electrical isolation of the cathode and anode electrodes from each other and which allows an air tight enclosure for preventing an inflow of oxygen to the semiconductor element. The cathode and anode electrodes, the ceramic ring and potentially further parts such as flanges thus create a closed space of housing in which the semiconductor element is placed. The closed space of the housing of a high power semiconductor device is usually filled with an inert gas.
In JP 05304179 in FIG. 8 and par. [0044] a ring shaped groove filled by a component 41 for adhesion, such as silicone rubber and polyimide, whereby there is no fluidly connection of at least a part of the first free portion (at the edge of the element) with a predetermined degassing point 31, 32, 33) of the housing for guiding an overpressure from the first free portion to the predetermined degassing 31, 32, 33 point. During production of semiconductor device of JP 05304179 when placing the semiconductor base substance 2 on the first electrode plate 51 air could be enclosed between the holes 31, 32, 33, whereby these holes 31, 32, 33 enable the air to exhaust, see par. [0077] in connection with FIG. 8.
Also U.S. Pat. No. 5,519,231 shows in FIG. 4 holes, 20b, 20c, 20d, 20e for exhausting air or gas during production (see col. 11, lines 46-57). Additionally, DE 43 210 53 A1 discloses in FIG. 2 also holes 31c, 31d for exhausting air or gas during production (see col. 6, lines 6-11; col. 5, lines 19-31; col. 19, line 50-col. 20, line 3).
It is known for power semiconductor devices that under circumstances they may fall into a failure mode during operation, when a point of breakdown was created in the semiconductor element and subsequently a high current density flows through this point of breakdown. Without providing respective counter measures, these kinds of failures may lead to the formation of hot plasma and/or gas inside the housing of the high power semiconductor device, whereby plasma is defined as ionized gas. Such failures may thus lead to a damage of the power semiconductor device.